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346 lines
10 KiB
C
346 lines
10 KiB
C
/* Machine-dependent ELF dynamic relocation inline functions. m68k version.
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Copyright (C) 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc.,
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59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
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#ifndef dl_machine_h
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#define dl_machine_h
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#define ELF_MACHINE_NAME "m68k"
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#include <sys/param.h>
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/* Return nonzero iff E_MACHINE is compatible with the running host. */
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static inline int
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elf_machine_matches_host (Elf32_Half e_machine)
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{
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switch (e_machine)
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{
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case EM_68K:
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return 1;
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default:
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return 0;
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}
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}
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/* Return the link-time address of _DYNAMIC. Conveniently, this is the
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first element of the GOT. This must be inlined in a function which
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uses global data. */
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static inline Elf32_Addr
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elf_machine_dynamic (void)
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{
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register Elf32_Addr *got asm ("%a5");
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return *got;
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}
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/* Return the run-time load address of the shared object. */
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static inline Elf32_Addr
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elf_machine_load_address (void)
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{
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Elf32_Addr addr;
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asm ("lea _dl_start(%%pc), %0\n\t"
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"sub.l _dl_start@GOT.w(%%a5), %0"
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: "=a" (addr));
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return addr;
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}
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/* Set up the loaded object described by L so its unrelocated PLT
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entries will jump to the on-demand fixup code in dl-runtime.c. */
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static inline int
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elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
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{
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Elf32_Addr *got;
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extern void _dl_runtime_resolve (Elf32_Word);
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extern void _dl_runtime_profile (Elf32_Word);
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if (l->l_info[DT_JMPREL] && lazy)
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{
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/* The GOT entries for functions in the PLT have not yet been
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filled in. Their initial contents will arrange when called
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to push an offset into the .rela.plt section, push
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_GLOBAL_OFFSET_TABLE_[1], and then jump to
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_GLOBAL_OFFSET_TABLE_[2]. */
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got = (Elf32_Addr *) l->l_info[DT_PLTGOT]->d_un.d_ptr;
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got[1] = (Elf32_Addr) l; /* Identify this shared object. */
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/* The got[2] entry contains the address of a function which gets
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called to get the address of a so far unresolved function and
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jump to it. The profiling extension of the dynamic linker allows
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to intercept the calls to collect information. In this case we
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don't store the address in the GOT so that all future calls also
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end in this function. */
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if (profile)
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{
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got[2] = (Elf32_Addr) &_dl_runtime_profile;
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if (_dl_name_match_p (_dl_profile, l))
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{
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/* This is the object we are looking for. Say that we really
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want profiling and the timers are started. */
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_dl_profile_map = l;
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}
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}
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else
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/* This function will get called to fix up the GOT entry indicated by
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the offset on the stack, and then jump to the resolved address. */
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got[2] = (Elf32_Addr) &_dl_runtime_resolve;
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}
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return lazy;
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}
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/* This code is used in dl-runtime.c to call the `fixup' function
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and then redirect to the address it returns. */
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#define TRAMPOLINE_TEMPLATE(tramp_name, fixup_name) \
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"| Trampoline for " #fixup_name "
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.globl " #tramp_name "
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.type " #tramp_name ", @function
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" #tramp_name ":
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| Save %a0 (struct return address) and %a1.
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move.l %a0, -(%sp)
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move.l %a1, -(%sp)
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| Call the real address resolver.
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jbsr " #fixup_name "
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| Restore register %a0 and %a1.
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move.l (%sp)+, %a1
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move.l (%sp)+, %a0
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| Pop parameters
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addq.l #8, %sp
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| Call real function.
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jmp (%d0)
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.size " #tramp_name ", . - " #tramp_name "\n"
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#ifndef PROF
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#define ELF_MACHINE_RUNTIME_TRAMPOLINE \
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asm (TRAMPOLINE_TEMPLATE (_dl_runtime_resolve, fixup) \
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TRAMPOLINE_TEMPLATE (_dl_runtime_profile, profile_fixup));
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#else
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#define ELF_MACHINE_RUNTIME_TRAMPOLINE \
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asm (TRAMPOLINE_TEMPLATE (_dl_runtime_resolve, fixup) \
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".globl _dl_runtime_profile\n" \
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".set _dl_runtime_profile, _dl_runtime_resolve");
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#endif
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#define ELF_MACHINE_RUNTIME_FIXUP_ARGS long int save_a0, long int save_a1
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/* Mask identifying addresses reserved for the user program,
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where the dynamic linker should not map anything. */
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#define ELF_MACHINE_USER_ADDRESS_MASK 0x80000000UL
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/* Initial entry point code for the dynamic linker.
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The C function `_dl_start' is the real entry point;
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its return value is the user program's entry point. */
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#define RTLD_START asm ("\
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.text
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.globl _start
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.type _start,@function
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_start:
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move.l %sp, -(%sp)
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jbsr _dl_start
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addq.l #4, %sp
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.globl _dl_start_user
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.type _dl_start_user,@function
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_dl_start_user:
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| Save the user entry point address in %a4.
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move.l %d0, %a4
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| Point %a5 at the GOT.
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lea _GLOBAL_OFFSET_TABLE_@GOTPC(%pc), %a5
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| Remember the highest stack address.
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move.l %sp, ([__libc_stack_end@GOT.w, %a5])
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| See if we were run as a command with the executable file
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| name as an extra leading argument.
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move.l ([_dl_skip_args@GOT.w, %a5]), %d0
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jeq 0f
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| Pop the original argument count
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move.l (%sp)+, %d1
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| Subtract _dl_skip_args from it.
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sub.l %d0, %d1
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| Adjust the stack pointer to skip _dl_skip_args words.
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lea (%sp, %d0*4), %sp
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| Push back the modified argument count.
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move.l %d1, -(%sp)
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0: | Push the searchlist of the main object as argument in
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| the _dl_init_next call below.
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move.l ([_dl_main_searchlist@GOT.w, %a5]), %d2
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| First dun the pre-initializers.
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0: move.l %d2, -(%sp)
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| Call _dl_preinit_next to return the address of an pre-initializer
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| function to run.
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bsr.l _dl_preinit_next@PLTPC
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add.l #4, %sp | Pop argument.
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| Check for zero return, when out of pre-initializers.
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tst.l %d0
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jeq 0f
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| Call the shared object pre-initializer function.
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move.l %d0, %a0
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jsr (%a0)
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| Loop to call _dl_preinit_next for the next pre-initializer.
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jra 0b
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0: move.l %d2, -(%sp)
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| Call _dl_init_next to return the address of an initializer
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| function to run.
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bsr.l _dl_init_next@PLTPC
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add.l #4, %sp | Pop argument.
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| Check for zero return, when out of initializers.
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tst.l %d0
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jeq 1f
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| Call the shared object initializer function.
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| NOTE: We depend only on the registers (%d2, %a4 and %a5)
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| and the return address pushed by this call;
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| the initializer is called with the stack just
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| as it appears on entry, and it is free to move
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| the stack around, as long as it winds up jumping to
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| the return address on the top of the stack.
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move.l %d0, %a0
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jsr (%a0)
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| Loop to call _dl_init_next for the next initializer.
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jra 0b
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1: | Clear the startup flag.
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clr.l ([_dl_starting_up@GOT.w, %a5])
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| Pass our finalizer function to the user in %a1.
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move.l _dl_fini@GOT.w(%a5), %a1
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| Initialize %fp with the stack pointer.
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move.l %sp, %fp
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| Jump to the user's entry point.
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jmp (%a4)
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.size _dl_start_user, . - _dl_start_user
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.previous");
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/* Nonzero iff TYPE describes a relocation that should
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skip the executable when looking up the symbol value. */
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#define elf_machine_lookup_noexec_p(type) ((type) == R_68K_COPY)
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/* Nonzero iff TYPE describes relocation of a PLT entry, so
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PLT entries should not be allowed to define the value. */
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#define elf_machine_lookup_noplt_p(type) ((type) == R_68K_JMP_SLOT)
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/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
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#define ELF_MACHINE_JMP_SLOT R_68K_JMP_SLOT
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/* The m68k never uses Elf32_Rel relocations. */
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#define ELF_MACHINE_NO_REL 1
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static inline void
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elf_machine_fixup_plt (struct link_map *map, const Elf32_Rela *reloc,
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Elf32_Addr *reloc_addr, Elf32_Addr value)
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{
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*reloc_addr = value;
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}
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/* Return the final value of a plt relocation. On the m68k the JMP_SLOT
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relocation ignores the addend. */
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static inline Elf32_Addr
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elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc,
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Elf32_Addr value)
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{
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return value;
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}
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#endif /* !dl_machine_h */
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#ifdef RESOLVE
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/* Perform the relocation specified by RELOC and SYM (which is fully resolved).
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MAP is the object containing the reloc. */
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static inline void
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elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,
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const Elf32_Sym *sym, const struct r_found_version *version,
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Elf32_Addr *const reloc_addr)
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{
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if (ELF32_R_TYPE (reloc->r_info) == R_68K_RELATIVE)
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*reloc_addr = map->l_addr + reloc->r_addend;
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else
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{
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const Elf32_Sym *const refsym = sym;
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Elf32_Addr value = RESOLVE (&sym, version, ELF32_R_TYPE (reloc->r_info));
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if (sym)
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value += sym->st_value;
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switch (ELF32_R_TYPE (reloc->r_info))
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{
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case R_68K_COPY:
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if (sym == NULL)
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/* This can happen in trace mode if an object could not be
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found. */
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break;
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if (sym->st_size > refsym->st_size
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|| (sym->st_size < refsym->st_size && _dl_verbose))
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{
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extern char **_dl_argv;
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const char *strtab;
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strtab = (const void *) map->l_info[DT_STRTAB]->d_un.d_ptr;
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_dl_sysdep_error (_dl_argv[0] ?: "<program name unknown>",
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": Symbol `", strtab + refsym->st_name,
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"' has different size in shared object, "
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"consider re-linking\n", NULL);
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}
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memcpy (reloc_addr, (void *) value, MIN (sym->st_size,
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refsym->st_size));
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break;
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case R_68K_GLOB_DAT:
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case R_68K_JMP_SLOT:
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*reloc_addr = value;
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break;
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case R_68K_8:
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*(char *) reloc_addr = value + reloc->r_addend;
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break;
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case R_68K_16:
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*(short *) reloc_addr = value + reloc->r_addend;
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break;
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case R_68K_32:
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*reloc_addr = value + reloc->r_addend;
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break;
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case R_68K_PC8:
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*(char *) reloc_addr
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= value + reloc->r_addend - (Elf32_Addr) reloc_addr;
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break;
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case R_68K_PC16:
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*(short *) reloc_addr
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= value + reloc->r_addend - (Elf32_Addr) reloc_addr;
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break;
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case R_68K_PC32:
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*reloc_addr = value + reloc->r_addend - (Elf32_Addr) reloc_addr;
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break;
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case R_68K_NONE: /* Alright, Wilbur. */
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break;
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default:
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_dl_reloc_bad_type (map, ELF32_R_TYPE (reloc->r_info), 0);
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break;
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}
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}
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}
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static inline void
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elf_machine_lazy_rel (struct link_map *map,
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Elf32_Addr l_addr, const Elf32_Rela *reloc)
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{
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Elf32_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
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if (ELF32_R_TYPE (reloc->r_info) == R_68K_JMP_SLOT)
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*reloc_addr += l_addr;
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else
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_dl_reloc_bad_type (map, ELF32_R_TYPE (reloc->r_info), 1);
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}
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#endif /* RESOLVE */
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